This invention relates to nuclear power plants, and more particularly to a valve control system for overpressure protection of a nuclear reactor coolant system.
In accordance with current industry code requirements, all nuclear power plants must have some form of overpressure protection when operating at normal (at power) system temperature and pressures. Overpressure protection is provided by the use of self-actuating safety valves which open at predetermined set pressures. In addition, overpressure protection is required even when the reactor is operating in low temperature modes such as during heatup or cooldown. This latter type of protection, often referred to as Low Temperature Overpressure Protection (LTOP), is intented to preclude the potential of brittle fracture of the nuclear steam supply system components.